LHVM (Lionhead Virtual Machine)

Lionhead Virtual Machine Specification

Lionhead Virtual Machine (LHVM) is a simple stack based virtual machine used to execute bytecode generated from a proprietary scripting language to generate the narrative world of Black & White.

Opcodes

The virtual machine consists of a total of 31 different opcodes, each instruction also has two additional enum values: access type is either 1: use stack or 2: use variable. And data type which can can be any of the following:

• 0x01: Integer Value
• 0x02: Float Value
• 0x03: Vector Value (Tends to be 3 floats pushed and popped on the stack equally)
• 0x04: ?
• 0x05: ?
• 0x06: Boolean value (0 = false, 1 = true)

Below is a list of defined behaviours combinations of opcodes and data types should use, this should be a comprehensive list of all needed to implement a fully working LHVM, however it is unknown if compiled bytecodes have any undefined behaviours.

Opcode	Data Type	Mnemonic	Description
0x00		END	Stops the execution of the current script task.
0x01		WAIT	Waits at this instruction until a value can be popped from the stack.
0x02		PUSH	Pushes a literal value onto the stack, Value can either be literal or a reference to a variable depending on Access.
0x03		POP	Pops a value from the stack either into null or into a referenced variable.
0x04	0x01	ADD	Pops 2 ints, adds them, pushes 1 int.
0x04	0x02	ADDF	Pops 2 floats, adds them, pushes 1 float.
0x04	0x03	ADDV	Pops 6 vfloats, adds them, pushes 3 vfloats.
0x05		CALL	Calls a "native" function using the Value as the function identifer. (0 -> 464)
0x06	0x01	MINUS	Pops 2 ints, minuses them, pushes 1 int.
0x06	0x02	MINUSF	Pops 2 floats, minuses them, pushes 1 float.
0x06	0x03	MINUSV	Pops 6 vfloats, minuses them, pushes 3 vfloats.
0x07	0x01	UMINUS	Pops 1 int and pushes the negated 1 int.
0x07	0x02	UMINUSF	Pops 1 float and pushes the negated 1 float.
0x07	0x03	UMINUSV	Pops 3 vfloat and pushes the negated 3 vfloat.
0x08	0x01	TIMES	Pops 2 ints, multiplies them, pushes 1 int.
0x08	0x02	TIMESF	Pops 2 floats, multiplies them, pushes 1 float.
0x08	0x03	TIMESV	Pops 6 vfloats, multiplies them, pushes 3 vfloats.
0x09	0x01	DIVIDE	Pops 2 ints, divides them, pushes 1 int.
0x09	0x02	DIVIDEF	Pops 2 floats, divides them, pushes 1 float.
0x09	0x03	DIVIDEV	Pops 6 vfloats, divides them, pushes 3 vfloats.
0x0A	0x01	MODULUS	Pops 2 ints, modulus them, pushes 1 int.
0x0A	0x02	MODULUSF	Pops 2 floats, modulus them, pushes 1 float.
0x0B		NOT	Pops 1 value, checks if it's equal to zero, pushes 1 boolean.
0x0C		AND	Pops 2 values, val1 && val2, pushes 1 boolean.
0x0D		OR	Pops 2 values, `val1
0x0E	0x01	EQ	Pops 2 integer values, checks equality, pushes 1 boolean value.
0x0E	0x02	EQ	Pops 2 float values, checks equality, pushes 1 boolean value.
0x0E	0x0*	EQ	Pops zero values, pushes 1 false boolean value.
0x0E	0x06	EQ	Pops 2 boolean values, checks equality, pushes 1 boolean value.
0x0F	0x01	NEQ	Pops 2 integer values, checks equality, pushes 1 boolean value.
0x0F	0x02	NEQ	Pops 2 float values, checks equality, pushes 1 boolean value.
0x0F	0x0*	NEQ	Pops zero values, pushes 1 false boolean value.
0x0F	0x06	NEQ	Pops 2 boolean values, checks equality, pushes 1 boolean value.
0x10	0x01	GEQ	Pops 2 integer values, checks greater than or equal to, pushes 1 boolean value.
0x10	0x02	GEQ	Pops 2 float values, checks greater than or equal to, pushes 1 boolean value.
0x10	0x0*	GEQ	Pops zero, pushes 1 false boolean value.
0x11	0x01	LEQ	Pops 2 integer values, checks less than or equal to, pushes 1 boolean value.
0x11	0x02	LEQ	Pops 2 float values, checks less than or equal to, pushes 1 boolean value.
0x11	0x0*	LEQ	Pops zero, pushes 1 false boolean value.
0x12	0x01	GT	Pops 2 integer values, checks greater than, pushes 1 boolean value.
0x12	0x02	GT	Pops 2 float values, checks greater than, pushes 1 boolean value.
0x12	0x0*	GT	Pops zero, pushes 1 false boolean value.
0x13	0x01	LT	Pops 2 integer values, checks less than, pushes 1 boolean value.
0x13	0x02	LT	Pops 2 float values, checks less than, pushes 1 boolean value.
0x13	0x0*	LT	Pops zero, pushes 1 false boolean value.
0x14		JUMP	Sets the current instruction address to the value.
0x15		SLEEP	Pops 1 float and sleeps for that specific time. Pushes 1 boolean.
0x16		EXCEPT	todo...
0x17		INTCAST	Pops 1 value, casts it to an integer and pushes 1 integer value.
0x18		RUN	Runs another script task independently. Value is script id.
0x19		ENDEXCEPT	todo...
0x1A		RETEXCEPT	todo...
0x1B		FAILEXCEPT	todo...
0x1C		BRKEXCEPT	todo...
0x1D	0x01	SWAP	Pops 2 ints, swaps their order, pushes 2 ints.
0x1D		SWAP	todo...
0x1E		LINE	Nothing, just specifies the source code file line.

Native Functions

todo: auto generate these from IDA